The objective of this proposal is to investigate the abilities of an intact sense (e.g., vision) to compensate for the loss of another sense (e.g., audition). To this end, visual abilities of deaf adults, with a particular focus on motion perception, will be studied. If the visual system can compensate for the loss of auditory sensation in deaf subjects, deaf subjects may have enhanced motion perception abilities. Using psychophysical tests, comparisons will be made of motion processing in the deaf to motion processing in two groups of hearing subjects: 1) "hearing of deaf (HD) adults who have American Sign Language (ASL) as their first language, and 2) adults with no ASL history. Inclusion of HD hearing adults will serve to separate the effects of auditory deprivation (unique to the deaf) from reliance on a visual language (common to both deaf and HD subjects). In addition, employing a variety of lower- vs. higher-level motion tasks will reveal where in the visual processing stream differences between deaf and hearing subjects occur. Finally, once the tasks that best differentiate deaf vs. hearing performance are identified, functional MRI will be used to localize areas of visual cortex that may underlie the perceptual differences. These experiments will teach us about the perceptual limitations and potentials of cross-modal plasticity. They may also reveal differences among specific brain areas in susceptibility to, and ability to compensate for, early sensory insults. These results may be useful in designing compensatory training programs for sensory-deprived children that exploit the early plasticity of those brain areas most receptive to altered sensory experience.